3.5 Shift points

Besides my Alternator problems (see 2000 Alternator Blues), my biggest complaint with my 3.5 Intrigue is the transmission shift point programming. On my way home each day, I go up a steep grade on the Interstate. My Intrigue does not kickdown to third gear until I have lost a lot of speed and been about overrun by a semi or two. My way of coping is to manually shift the tranny into third at the bottom of the hill. This is the 21st century, and we now have electronically controlled transmissions to solve these problems. Because GM designed this engine on the cheap and forwent the variable valve timing, the 3.5 is anemic on the low end. The least they could have done to help us out in that case is program the tranny to kick down readily. Is this something that can be reprogrammed?